In recent years, the EV (electric vehicle) or the PHEV (hybrid electric vehicle) have achieved great improvements in the core technologies and have been gradually entering the stage of practical use and small scale industrialization.
Heating is one of the important technologies of the EV (electric vehicle) or the PHEV (hybrid electric vehicle). Under one circumstance, when the temperature is extremely low, the high voltage battery pack needs to be heated firstly before it can be charged. Under another circumstance, the power from the high voltage battery pack is needed to be converted to heat energy to, for example, warm the EV (electric vehicle) or the PHEV (hybrid electric vehicle), defrost or demist. But the heating technologies at present often make the battery charge system bigger volume, higher cost, higher loss and lower efficiency. FIG. 1A and FIG. 1B show a block diagram of a battery charge system according to the prior art. As shown in FIG. 1A, in the preheating mode before the high voltage battery pack 32 can be charged, the power from the alternating current (AC) terminal is transmitted to the electrothermal element 13 by the AC/direct current (DC) converter 111, the DC/DC converter 112, and the PWM DC/DC converter 33, and then the electrothermal element 13 converts the electric power into heat energy to warm the EV or the PHEV. As shown in FIG. 1B, in the temperature conditioning mode, the power from the high voltage battery pack 32 is transmitted to the electrothermal element 13 by the PWM DC/DC converter 33, and then the electrothermal element 13 converts the electric power into heat energy to condition the temperature of the EV or the PHEV. So there needs an additional special PWM DC/DC converter and a controller correspondingly to control it to output the electric power to the electrothermal element 13, which makes the battery charge system bigger volume, higher cost, higher loss and lower efficiency.
So there is a need to provide a new heating technology to make a smaller volume, lower cost, lower loss and higher efficiency battery charge system.